A resent email from Mozilla said to go to preferences to make a change. I can't find it. It doesn't appear under the Firefox tab in the upper left or anywhere else I've looked. Where would it be?
Mozilla doesn't send email about changes to Firefox. Sounds like someone was trying to exploit you into making a nefarious changes to Firefox.
* Linux: Edit > Preferences
* Mac: Firefox > Preferences
* Windows: Firefox > Options or Tools > Options
I think I could have been clearer. The email was Mozilla's Firefox and You article "6 Tips to Stay Safe While Browsing"